const errors = require('./errors'),

fs = require("fs"),

peg = require('pegjs'),

tracer = require('pegjs-backtrace'),

util = require('util'),

debug = require('debug')('b3');

const SYSCALL_TYPE = 'SYSCALL';

const ALERT_TYPE = 'ALERT';

const ERROR_TYPE = 'ERROR';

const STOPPED_TYPE = 'STOPPED';

module.exports = {

syscallType: SYSCALL_TYPE,

alertType: ALERT_TYPE,

errorType: ERROR_TYPE,

stoppedType: STOPPED_TYPE,

initialize: function(options={}) {

let grammar = fs.readFileSync(__dirname + '/../grammar.pegjs', 'utf8');

this.trace = options.hasOwnProperty('trace') && options.trace == true;

this.parser = peg.generate(grammar, {cache: true, optimize: 'speed', trace: this.trace});

},

parseLine: function(line) {

if(line == null || line.trim().length <= 0) {

return null;

}

// this will match lines that are marked as "unfinished" or "resume"

if(line.match(/<\.\.\./) || line.match(/\.\.\.>/)) {

throw new errors.UnfinishedSyscallException('Unfinished/resume line encountered');

}

try {

return this.parser.parse(line, {tracer: this.getTracer(line)});

} catch(e) {

debug("Exception caught");

debug(util.format(e));

throw e;

}

},

getTracer: function(line) {

if(!this.trace) {

return null;

}

return new tracer(line, {showTrace: true});

}

};